Method and device for cooling beverages

ABSTRACT

The invention relates to a beverage dispenser ( 1000 ) for dispensing beverages, that comprises: a refrigeration circuit ( 41 ); a tank ( 10 ) for containing said coolant at a liquid state coming from a first duct ( 20 ) in the lower portion thereof and evaporating said coolant into a gaseous state, and for containing said coolant in a gaseous state in the upper portion thereof; a second duct ( 30 ) for collecting the coolant at the gaseous state from said tank ( 10 ); at least one duct ( 40 ) for circulating said beverage to be dispensed inside said tank ( 10 ) and according to a thermal exchange relation with the coolant at the liquid and/or gaseous state.

SUBJECT OF THE INVENTION

The present invention relates to a device and a method for cooling and dispensing beverages. In particular, the invention relates to a device and to a method for cooling and dispensing beer and other beverages in “flying pump” mode.

TECHNOLOGICAL BACKGROUND

Systems designed to dispense beverages, such as beer, sparkling wines, sodas, etc., while maintaining the beverages at a given temperature, which may vary from one beverage to another, have been known for a long time. In the case of beer for example, it is known that it freezes below a temperature of −1.5° C. and foams above 4° C., and that the tasting temperature depends on the type of beer (and therefore, depending on the type of beer, the temperature allows the beverage to reveal its taste, flavor and aroma). Typically, two methods are known for cooling beverages.

The first method is that in which a coil or a tank containing a beverage is immersed either in an ice bath or in a water bath refrigerated by a conventional refrigerating unit. In this regard, the reader may refer to the apparatus described in patent FR2684088. If the coil or the tank is immersed in an ice bath, the main drawbacks that may be observed are the low efficiency of heat transfer to the ice and its cost, and also the difficulty of obtaining and transporting blocks of ice of limited longevity. If the coil or the tank is immersed in a water bath refrigerated by a conventional refrigerating unit, the main drawbacks of such an apparatus that may be observed are the need to have a tank of large size in order to contain the refrigerated water, the long time to fill the tank with water, (which is not easy for dispensing in “flying pump” mode) and the time to cool the volume of water and therefore the considerable delay between starting the apparatus and dispensing the first cooled beverage.

The second method is that in which a tank containing a beverage is surrounded by an evaporator (and therefore in direct contact with the latter) of a conventional cooling circuit. The tank is integrated into a lagged compartment and is cooled by heat exchange with the evaporator. In this regard, the reader may refer to U.S. Pat. No. 3,712,514, the main drawbacks of which are the time to cool the tank, which must be entirely cooled before dispensing, the large dimensions of the lagged chamber containing the tank and evaporator, and the presence of air (with a very low thermal exchange coefficient) between the tank and the evaporator.

A refrigerated beverage dispenser is also known from FR 2815024 in which the beverage is cooled by two refrigerating means. However, this dispenser is suitable for a low beverage flow rate. In addition, that document describes a method comprising both the method described by FR2684088 and that described by U.S. Pat. No. 3,712,514.

A beverage cooling system is also known from U.S. Pat. No. 5,970,732 in which a beverage is cooled by means of a heat exchanger. In this system, the heat exchange takes place by direct thermal contact between the beverage and the coolant circulating inside this exchanger, these two liquids being separated by a metal surface. However, this system has the following drawbacks: the construction of such a system is complicated and expensive due to the presence of all the plates that are placed at a precise distance δ and are difficult to produce. Consequently, due to the presence of zones that are difficult to access, it is practically impossible to clean the inside of the heat exchanger. In addition, there is a high risk in this system of contaminating the beverage with the refrigerating gas, due to a sealing fault (and therefore a fault in a weld or a perforation in the zone separating the beverage from the gas). Moreover, the heat exchanger requires, in order for it to operate properly, a liquid separator 3. Due to the shape of the latter, the heat exchanger cannot be easily lagged. Furthermore, this system can cool only a single beverage duct at a time. Therefore, if a large output is required and a first barrel is empty, before being able to continue to dispense it is necessary to wait until the empty barrel has been replaced with a full barrel, or else there must be a second heat exchanger for standby use.

Three types of compressor units used in this type of application are known:

-   -   open unit: in which the compressor and the motor are separate,         but connected together by belts or a mechanical transmission.         This compressor unit is available in single-phase or three-phase         form. However, this compressor unit is very heavy, bulky and         expensive;     -   semi-sealed unit: in which the motor and the compressor are         directly assembled, one against the other. The coupling between         the motor and the compressor is therefore not accessible (unless         the two parts are separated by disconnecting them). This         compressor unit is therefore repairable. However, this         compressor unit is very expensive and exists only in three-phase         form and above 1.5 hp. This type of compressor unit is therefore         not appropriate for a dispenser in flying pump mode as it         requires a three-phase connection;     -   a sealed unit: in which the motor and the compressor are         confined in a non-deformable hermetically sealed bell, hence         their name. This compressor unit is available in single-phase         form (for low power levels, i.e. below 1.5 hp). This unit is         provided with a relay and a starting capacitor and sometimes         also with a permanent capacitor. However, there is a risk in         this compressor unit of said relay and the starting capacitor         overheating when it is frequently started and stopped.

One object of the invention is to provide a cooled-beverage dispenser that does not have all these disadvantages.

In particular, another object of the invention is to provide a beverage dispenser that enables a beverage source to be cooled continuously and instantaneously, including when the barrel containing a beverage is at a high temperature without any intermediary between the refrigerant and the beverage duct. Yet another object of the invention is to provide a beverage dispenser enabling beverages to be cooled without the need either for water, ice bath nor any mass or stirrer for creating a reserve and a heat exchange. A final object of the invention is to provide a beverage dispenser which can be used in “flying pump” mode, and therefore a dispenser that can be easily moved, is easy to install and enables cooled beverages to be dispensed shortly after installation.

SUMMARY OF THE INVENTION

The present invention relates to a beverage dispenser for dispensing a beverage comprising:

-   -   a refrigeration circuit comprising:         -   a compressor which compresses the refrigerant in the gas             phase, while increasing its temperature, said compressor             being a single-phase compressor;         -   a condenser which makes the temperature drop and condenses             the refrigerant gas;         -   means designed to reduce the pressure of said refrigerant,             passing via a first line, said first line being designed to             circulate said refrigerant in liquid form;     -   a tank designed to contain said refrigerant in liquid form         coming from this first line in its lower part and to allow said         refrigerant to evaporate in gaseous form, and designed to         contain said refrigerant in gaseous form in its upper part;     -   a second line designed to withdraw the refrigerant in gaseous         form from said tank; and     -   at least one duct designed to circulate said beverage to be         dispensed within said tank and in heat exchange relationship         with the refrigerant in liquid and/or gaseous form.

In a preferred embodiment of the invention, the drinks dispenser further comprises:

-   -   an auxiliary circuit connected to the refrigeration circuit by         two connections and, the first of which lying between the outlet         of the compressor and the condenser and the second lying between         the inlet of the compressor and the tank, respectively;     -   two non-return valves placed between the first connection and         the condenser and between the tank and the second connection,         respectively, which are designed to automatically shut off if         the refrigerant refluxes from the condenser to said auxiliary         circuit or from said auxiliary circuit to the tank;     -   a balancing valve, normally open when the compressor is not         operating, placed inside the auxiliary circuit in order to         balance the pressure inside said auxiliary circuit and closed         when starting said compressor; and     -   a magnetic valve, normally closed when the compressor is not         operating, placed between the condenser and the tank, in order         to stop the flow of refrigerant from the condenser to the tank,         and open when starting said compressor.

Advantageously, the beverage dispenser comprises a thermostat designed to measure the temperature inside said tank and to stop or restart said compressor. This restarting is preferably carried out after a minimum delay of four seconds.

In a preferred embodiment of the invention, said tank comprises, inside, a cylinder welded to the bottom of said tank and open at the top, designed to collect the refrigerant in gaseous form in the upper part of said tank and discharge said refrigerant by the second line toward said compressor. This cylinder also makes it possible to raise, for a given volume of refrigerant, the level of the latter inside the tank so as to improve the heat exchange between the fluid and the beverage.

Advantageously, said at least one duct is wound around said cylinder.

Advantageously, said duct is a coil, which may be made of stainless steel.

In another preferred variant of the invention, said at least one duct is inserted into a tube in order to form a double-walled duct so as to avoid any risk of food contamination in the event of the coil leaking.

Advantageously, this tube is made of copper.

Preferably, the beverage dispenser comprises a pressure safety switch designed to start or stop said compressor.

Finally, the present invention relates to the use of a beverage dispenser in flying pump mode.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a simplified view of a beverage cooling device of the prior art.

FIG. 2 shows a schematic view of a preferred embodiment of a beverage dispenser according to the invention.

FIG. 3 shows a schematic view of a general operating mode of the beverage dispenser of FIG. 2.

FIG. 4 illustrates an advantageous embodiment of the dispenser of FIG. 2.

DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT OF THE INVENTION

FIG. 1 is a simplified view of a beverage cooling device of the prior art in which a line 100 (for example a coil) transporting a beverage is immersed in a water bath containing ice.

FIG. 2 is a diagram showing the general principle of one operating mode of a beverage dispenser according to the invention. The dispenser 1000 comprises:

-   -   a source of refrigerant (such as a conventional refrigerating         circuit using for example R22, R404 or R407, or a liquefied gas         cylinder containing for example CO₂, etc . . . );     -   a lagged tank 10, in the form of cylinder 28 cm in diameter and         40 cm in height made of sheet metal 4 mm in thickness designed         to contain said refrigerant in the liquid form in its lower part         and to allow said refrigerant to evaporate, and designed to         contain the refrigerant in gaseous form in its upper part;     -   a first line 20 for transporting the refrigerant in liquid form         in the lower part of the tank 10;     -   a second line 30 designed to withdraw the refrigerant in gaseous         form from the upper part of the tank; and     -   a duct 40 designed to circulate the beverage to be dispensed         inside said tank and to cool it by heat exchange with the         refrigerant in liquid and gaseous form.

FIG. 3 shows schematically a preferred beverage dispenser in which the refrigerant source is a conventional refrigerating circuit, according to the invention. The dispenser 1000 comprises:

-   -   a refrigerating circuit 41 comprising:         -   a single-phase compressor unit 50 (hereafter for simplicity             called compressor 50) which compresses a refrigerant in             gaseous phase;         -   a condenser 60 which, cooled by water or by the external             air, makes the temperature drop and condenses the             refrigerant gas;         -   a dehydrater 70 and a pressure relief valve 80, which reduce             the pressure of said refrigerant flowing via the line 20             into the tank 10; and         -   a thermostat 90 designed to measure the temperature inside             said     -   an auxiliary circuit 42 connected to the refrigerating circuit         41 via two connections 42 a and 42 b, the first being between         the outlet of the compressor 50 and the condenser 60 and the         second being between the inlet of the compressor 50 and the tank         10;     -   two non-return valves 43 and 43′ placed between the connection         42 a and the condenser 60 and between the tank 10 and the         connection 42 b, respectively;     -   a normally open balancing valve 44 placed in the auxiliary         circuit 42; and     -   a normally closed magnetic valve 45 placed between the condenser         60 and the tank 10.

According to a preferred embodiment of the invention, the compressor 50 is chosen from hermetically sealed single-phase air-conditioning units. This choice is preferred to refrigerating compressors as they deliver higher power levels, and have neither relay nor start-up capacitor. This choice therefore has the advantage of being less expensive for the same power. In addition, they do not have the drawback due to the relay and the start-up capacitor overheating. These compressor units are designed at the outset for starting 7 to 8 times per hour with, each time, a minimum stoppage of 2 to 3 minutes. They exist in single-phase form and use the fluids R22, R404A, R507, R407C and R410A.

The power of said compressor 50 is calculated according to the desired beverage flow rate. In the case of a flying pump, the flow rate is calculated continuously with a differential of about 26° C. For example, to cool 150 liters of beer from 27° C to 1° C in one hour, the compressor 50 must have a power of about 4000 W (at a 0° C. evaporation temperature).

The preferred beverage dispenser 1000 is used in the following manner. When the dispenser 1000 is turned on and when the thermostat 90 controls the start-up compressor 50, the latter compresses the refrigerant in the gas phase. During operation of the compressor 50, the magnetic valve 44, which is powered in parallel with said compressor 50, is closed and consequently prevents circulation of the refrigerant in the auxiliary circuit 42 and therefore prevents balancing between the pressure of the refrigerant entering the compressor 50 and that of the refrigerant leaving said compressor. Likewise, during operation of the compressor 50, the magnetic valve 45 is open, allowing free circulation of the refrigerating circuit 41. The refrigerant in gaseous phase, compressed by the compressor 50, passes via the condenser 60 which, cooled by water or by the external air, causes its temperature to drop and condenses it in liquid form. The refrigerant in liquid form passes via a dehydrater 70 and via a pressure relief valve 80 which ensure that the tank 10 is properly filled, while still controlling the correct evaporation of the refrigerant. This first part of the cooling circuit is characterized by a high pressure of the refrigerant leaving the compressor 50 and entering the pressure relief valve 80. When the refrigerant in liquid form enters the tank 10, passing via the pressure relief valve 80 and the line 20, it is deposited in the lower part of the tank 10 and boils off, extracting heat from its environment. The beverage, circulating in the duct 40, typically a stainless steel coil 21 mm in length, inside the tank 10 is consequently cooled by the heat exchange between this duct 40 and the refrigerant in liquid form and in gas form. To avoid any risk of the beverage leaking or being contaminated, the duct 40 is, in one embodiment of the invention, inserted into a copper tube, i.e. forming a double-walled duct with atmospheric pressure between the two walls. The refrigerant in gaseous form is discharged via the line 30, which conducts said refrigerant to the compressor 50. The second part of the cooling circuit is characterized by a low pressure of the refrigerant leaving the pressure relief valve 80 and entering the compressor 50.

When the compressor 50 is stopped, either when the temperature measured inside the tank 10 by the thermostat 90 reaches the required value, or when the dispenser is turned off, the magnetic valve 44 inside the auxiliary circuit 42 is opened, while the magnetic valve 45 is closed and the two non-return valves 43, 43′ automatically shut off the entire reflux of the refrigerant. In this way, it is possible to balance the pressure of the refrigerant in the auxiliary circuit 42 without balancing the pressure (and therefore the temperature) inside the tank 10 and the condenser 60. The balancing between the high pressure of the refrigerant leaving the compressor 50 and the low pressure of the refrigerant entering the compressor 50 enables the latter to be able to be easily restarted after a stoppage and to keep the temperature inside the tank 10 and the condenser 60 unchanged. Thanks to this mechanism, it is possible to use, as compressor, the compressor unit 50 described in paragraph [0027] and consequently avoid the use of a three-phase compressor unit requiring three-phase connection, which would limit the possibility of using the dispenser in flying pump mode. The single-phase compressor 50 has a power of between 0.5 and 4 hp.

As shown in FIG. 4, in another embodiment of the invention, the second line 30 may be replaced with a cylinder 31 welded to the bottom of the tank 10 and open at the top, enabling the refrigerant in gaseous form to leave the upper part of said tank 10. This cylinder 31 is placed inside the tank and is surrounded by the duct 40 containing the beverage. The presence of this cylinder 31 makes it possible to increase the level of refrigerant in liquid form contained in the tank 10 and thus improve the heat exchange between the beverage and the actual refrigerant, and therefore to reduce the time required to cool said beverage in the tank 10.

In another embodiment of the invention, the tank 10 may also have several beverage ducts 40 wound around the cylinder 11, without having need for other heat exchangers. This embodiment is particularly advantageous since it allows substantial and continuous dispensing of beverages and therefore no time is lost when changing empty barrels or allows different beverages to be chosen.

It is clear that when the inside of the tank 10 is at temperature, it is no longer necessary to cool the beverage, which might otherwise freeze or be too cold to be disposed.

According to the invention, it is possible, when the temperature of said tank 10 reaches an adjustable minimum threshold, to stop the compressor 50 by means of a thermostat 90.

With a mechanical thermostat, the stop/start differential is generally 2° C. and the reaction time is very long. The temperature variations would be large, the compressor would be restarted too late and the compressor power would be unable to compensate for the delay during an instantaneous flow.

In the invention, it is therefore preferable to use an electronic thermostat with which it is possible to set the temperature and the stop/start differential at a precision of 0.1° C. For example, the liquid leaving the evaporator is at 0.1° C., the compressor stops. If the differential is set to 0.4° C., the compressor restarts when the temperature in the evaporator is 0.5° C. Consequently, the stoppage time may be very short, most particularly if it is just at this very moment that the flow is started. The stoppage time must be designed to be as short as possible and must be regulated by the stop/start differential of the thermostat, the latter having a certain read rate (minimum/maximum rate). Whatever the read rate or the minimum differential, at least four seconds must be provided for stopping the compressor, no standard hermetically sealed single-phase compressor can normally be restarted after so short a time without the high-pressure/low-pressure fluid balancing mechanism described above in paragraph [0026].

When there is a large temperature difference (for example when switching the dispenser on), the actual temperature at evaporation will drop more quickly than the display on the electronic thermostat 90. In order not to drop below a threshold (typically 0° C.), the dispenser 1000 includes, in an advantageous embodiment of the invention, a pressure safety switch (not shown) capable of stopping the compressor 50 when the pressure inside the tank 10 reaches the value corresponding to the required temperature.

By means of the beverage dispenser according to the invention, it is possible to construct an apparatus which is compact and simple. In addition, the dispenser of the invention requires no cold reserve (ice or refrigerated water). In addition, the dispenser of the invention easily meets the safety standards by providing a double wall and inserting the stainless steel duct 40 inside a tube, for example a copper tube. Furthermore it has been found by experiment that the dispenser according to the invention can dispense, after a few minutes, a beverage at a temperature of 2° C., while the barrel containing this beverage is at 27° C. 

1-12. (canceled)
 13. A beverage dispenser for dispensing a beverage comprising: a refrigeration circuit comprising: a compressor operable to compress a refrigerant in gaseous form while increasing its temperature, said compressor being a single-phase compressor; a condenser operable to condense the refrigerant and lower its temperature; means designed to reduce a pressure of the refrigerant passing via a first line, the first line being designed to circulate said refrigerant in liquid form; a tank designed to contain said refrigerant in liquid form coming from this first line in its lower part and to allow said refrigerant to evaporate into gaseous form, and designed to contain said refrigerant in gaseous form in its upper part; a second line designed to withdraw the refrigerant in gaseous form from said tank; and at least one duct designed to circulate said beverage to be dispensed within said tank and in a heat exchange relationship with the refrigerant in liquid and/or gaseous form.
 14. The beverage dispenser as claimed in claim 13, further comprising: a circuit connected to said refrigeration circuit by a first and a second connection, the first connection lying between the outlet of the compressor and the condenser and the second connection lying between the inlet of the compressor and the tank, respectively; two non-return valves placed between the first connection and the condenser and between the tank and the second connection, respectively, which are designed to automatically shut off the reflux of said refrigerant from the condenser to said circuit or from said circuit to the tank; a balancing valve, normally open when the compressor is not operating, placed inside the circuit in order to balance the pressure inside said circuit and closed when starting said compressor; and a magnetic valve, normally closed when the compressor is not operating, placed between the condenser and the tank, in order to stop the flow of refrigerant from the condenser to the tank, and open when starting said compressor.
 15. The beverage dispenser as claimed in claim 13, comprising a thermostat designed to measure the temperature inside said tank and to start or stop said compressor.
 16. The beverage dispenser as claimed in claim 13, wherein said tank comprises, inside, a cylinder welded to the bottom of said tank and open at the top, designed to collect the refrigerant in gaseous fort in the upper part of said tank and discharge said refrigerant by the second line toward said compressor.
 17. The beverage dispenser as claimed in claim 16, wherein said at least one duct is wound around said cylinder.
 18. The beverage dispenser as claimed in claim 13, wherein said duct is a coil.
 19. The beverage dispenser as claimed in claim 8, wherein this coil is made of stainless steel.
 20. The beverage dispenser as claimed in claim 13, characterized in that said at least one duct is inserted into a tube in order to form a double-walled duct so as to avoid any risk of food contamination in the event of the coil leaking.
 21. The beverage dispenser as claimed in claim 20, wherein, said tube is made of copper.
 22. The beverage dispenser as claimed in claim 13, further comprising a pressure safety switch designed to start or stop said compressor.
 23. A use of the beverage dispenser as claimed in claim 13 for dispensing beverages in “flying pump” mode. 